Introduction: Hot thyroid nodules are seen in nearly 5% of patients with dominant nodules. The aim of this study was to evaluate the clinical course and results of different modalities of treatment during a ten year period. Materials and Methods: The study involved 132 out of 302 patients referring between 1987-1997 with hot thyroid nodules, diagnosed by clinical findings, thyroid function tests, and isotope scanning patients with at least 1-year regular follow-up were included, and were divided into two categories: hyperthyroid and euthyoid at the first presentation according to results of thyroid function tests. Results: The age range was 15-76 years and the duration of follow up was 1-10 years (4.9 ±3.5 m±SD). Female to male ratio was 7/1 (115 women, and 17 men). Half of the patients (66 cases) were thyrotoxic at the time of presentation. Eighteen of the euthyroid patients developed hyperthyroidism during the follow-up period. Sixty seven patients were treated with 8-25 mCi of I-131. Mean age was 47.5±13 years. Seventy three percent became euthyroid, 10.5% developed subclinical hyperthyroidism, and 16.5% developed clinical and subclinical hypothyroidism. Thyroid noduless disappeared in 21% of patients at the end of the study. Twenty-three patients underwent thyroidectomy. Mean age was 26.4± 7 years. Twenty-two percent of patients developed subclinical hyperthyroidism, and 8.6% developed hypothyroidism. The other half of the patients were euthyroid at the first presentation. Eighteen developed hyperthyroidism, sixteen underwent thyroidectomy. Thirty two patients remained euthyroid during the study, and ten hyperthyroid patients refused surgery or radioiodine treatment and were followed by antithyroid drug therapy. Conclusion: In this study both the treatments radioactive iodine and surgery were effective. Surgery, was the preferred method of treatment in younger patients. The frequency of hypothyroidism in patients who received radioactive iodine therapy was significantly higher as compared to surgery (p<005).